| 摘要 |
PURPOSE:To reduce parasitic resistance between a gate electrode and an ohmic electrode by forming an N-type AlGaAs layer, directly shaping the gate electrode and forming a high-concentration N-type GaAs layer up to a section extremely near to the gate electrode from the lower section of the ohmic electrode. CONSTITUTION:A gate electrode 14 consisting of a high melting-point metal is shaped onto an N-type AlGaAs layer 13, an insulating film is applied, and the insulating film is etched through reactive ion etching using a gas such as CF4 gas to leave the insulating films 15 only on the side surfaces of the gate electrode 14. A high-concentration N-type GaAs layer 16 having thickness such as 100Angstrom and carrier density such as 1X10<19>cm<-3> is grown selectively onto the N-type AlGaAs layer 13 in an epitaxial manner, employing the gate electrode 14 and the insulating film 15 as masks. Lastly, ohmic electrodes 17 are formed to the high-concentration N-type GaAs layers 16, thus shaping a field-effect transistor having a hetero-junction. The high-concentration N-type GaAs layers under the ohmic electrodes are formed up to sections extremely near to the gate electrode, thus acquiring excellent characteristics having small source resistance.
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